If a tree grows no ring and no one is around: how scientists deal with missing tree rings

Responding to a discrepancy between dendro-reconstruction and climate model during large volcano eruptions, scientists have been debating a missing tree ring (MTR) hypothesis—trees missing an annual ring at a large scale due to extreme cooling. Although both parties claim victory, their arguments are shown to be compromised in our analysis. On the one hand, one party’s argument based on the rarity of missing rings in current data cannot serve as evidence against the MTR because data collection methods already assume the MTR to be impossible; on the other, the other party’s hypothesis testing cannot support the MTR because it merely shows that data in volcanic years are less certain, which is known. Lastly, our analysis highlights a current knowledge gap in tree growth in extreme conditions and thus we urge scientists to perform natural and interventional experiments to understand tree growth limitations. Filling this gap will enhance dendro-reconstructions.